The entire disclosure of Japanese Patent Application No. 2010-77521, filed Mar. 30, 2010 is expressly incorporated herein by reference.
1. Technical Field
The present invention relates to a liquid ejecting apparatus that drives a pressure generator with an ejection pulse to thereby eject a liquid through a nozzle.
2. Related Art
A liquid ejecting apparatus currently known in the art drives a pressure generator such as a piezoelectric vibrator or a heating phase by applying an ejection drive pulse to the piezoelectric vibrator or heating phase. The ejection drive pulse causes the piezoelectric vibrator or heating phase to create pressure fluctuation of a liquid in a pressure chamber, which in turn causes the liquid to be ejected through a nozzle communicating with the pressure chamber. For example, in a printer disclosed in Japanese Patent No. 3412682, a drive pulse (drive waveform) is employed that includes a preparatory expansion process where a meniscus in the nozzle is drawn inward as much as possible toward the pressure chamber, a hold process where such a state is maintained as a standby state for a timing for ejecting an ink droplet, a first contraction process where the pressure chamber contracts thereby ejecting the ink droplet, and a second contraction process where a retracting action of the meniscus caused by a reaction of the ejection is suppressed. Thus, by contracting the pressure chamber after inwardly drawing the meniscus toward the pressure chamber in the expansion process, the ink droplet can be ejected utilizing a reaction of the retracting action of the meniscus.
In the liquid ejecting apparatus a phenomenon occurs wherein a rear portion of the ejected liquid droplet with respect to the moving direction stretches like a tail, known as tail drag. Such tail drag may create an irregular landing shape (dot shape) of the liquid droplet on a landing target. More specifically, although it is preferable that the landing shape assumes a circular or elliptical shape of a size specified according to desired image quality or performance level of the device, in the case where a part or whole of the tail flies separately from the main portion of the liquid droplet forming a satellite droplet, the satellite droplet may land on the landing target at a position separate from the main liquid droplet. Such irregularity of the landing shape results in degradation in image quality, for example in the case where an image is recorded on recording paper by a printer.